The brother of Mohammed Merah, the gunman who killed seven people, including three children in a series of attacks in south-west France, has been charged with complicity in the murders according to reports.

The French news agency AFP cited a judicial source as saying Abdelkader Merah had been charged, but that was not independently confirmed.

The 30-year-old faced four days of questioning in Paris after his brother was gunned down by police on Thursday at the end of an extended stand-off in his apartment in Toulouse.

Abdelkader Merah's girlfriend was reportedly also questioned, as was the Merah's mother who was released on Friday.

The AP said Abdelkader Merah had 'celebrated' his brother's death and may have been involved in sending other people from Toulouse to Iraq.

Police investigations have focused on how Mohammed Merah was able to acquire an arsenal of guns including an Uzi sub-machinegun, while apparently having little income and being under watch by the French authorities.

"We had to get him in the end. What else can we tell you," prosecutor Francois Molins said during a press conference.

Prosecutors have confirmed Merah was the gunman behind the three attacks that killed seven people in the region and had a stash of weapons.

Molins also confirmed that Merah filmed all three of his killings, including the murder of a three soldiers and the killing of four people at a Jewish school.

They said five police officers were injured in the operation. Prosecutors added that the 23-year-old may have become radicalised in prison, telling journalists that although he was known as a petty criminal "it was during his time in prison that he decided to read the Koran”.